90 degrees Fahrenheit is considered a hot temperature for most birds. However, whether or not 90 degrees is too hot depends on the specific species of bird and other factors like humidity, access to shade, and behavior adaptations for dealing with heat.
What is Considered a High Temperature for Birds?
The average body temperature for birds ranges from 104 to 113 degrees Fahrenheit. Due to their high normal body temperature, most birds can tolerate higher air temperatures than mammals before experiencing heat stress. However, temperatures over 90 degrees Fahrenheit are still considered hot for many avian species.
Birds are endothermic, meaning they generate internal body heat. This allows them to maintain a high, consistent body temperature compared to their surrounding environment. But it also means they have to work harder to cool themselves when air temperatures rise.
Evaporative cooling by panting or using gular fluttering is a primary way birds shed excess internal heat. This process becomes less effective as humidity increases since the air is already saturated with moisture.
How Heat Tolerance Varies Between Bird Species
Not all birds have the same level of heat tolerance. Species native to hot, tropical climates have adaptations to deal with high temperatures better than birds from temperate regions.
For example, the northern cardinal has a maximum temperature threshold around 105 degrees Fahrenheit before hyperthermia and death can occur. Whereas heat waves topping 118 degrees in the Sonoran desert have little effect on endangered Sonoran desert birds like the Gila woodpecker.
Birds also acclimate to the climate they live in. One study found that naive zebra finches had a preferred temperature range of 86–89°F. But finches conditioned to survive temperatures as high as 114°F for several weeks selected temperatures near 108°F when given a choice.
Other factors that affect heat tolerance in birds include:
- Size – Smaller birds dissipate heat faster with a higher surface area relative to volume.
- Coloration – Light colors reflect more radiant heat compared to dark feathers.
- Feather density – Birds with fewer feathers cope better in high temperatures.
- Fat stores – Excess fat insulates but also slows heat loss.
- Metabolic rate – Birds with higher metabolism generate more internal heat.
So a 90 degree day that a mourning dove shrugs off could threaten the life of a smaller finch. 90 degrees with moderate humidity is no problem for a bald eagle, but could lead to deadly overheating in a penguin.
Shade Access
Access to shade provides vital relief for birds during hot weather. Shaded areas allow body temperatures to decrease out of direct sunlight.
Birds will seek shade when possible at temperatures above their comfort range. One study found American kestrels began heat avoidance behaviors when ambient temperatures reached 86°F, including wing drooping, gaping, and leaving perches for cooler shaded spots.
Nest location is also crucial. Nests sites that are shaded, insulated, and exposed to breeze will keep eggs and chicks cooler than exposed, unprotected nests. Adult birds may soak their feathers in water to keep eggs moist and prevent overheating.
Artificial shade structures can give captive birds heat respite as well. Cooling perches, shade cloths over aviaries, fans, and misters are used in zoos to prevent hyperthermia.
Other Cooling Adaptations
Beyond seeking shade, birds have evolved other clever adaptations to cope with high heat:
- Gular fluttering – Fluttering their throat skin increases evaporative cooling. Panting through an open mouth has a similar effect.
- Wing drooping – Drooping and stretching their wings exposes more surface area for heat dissipation.
- Urohydrosis – Some arid-environment birds excrete water onto their legs and feet to promote evaporative cooling.
- Changing posture – Perching upright raises less of their body surface to the sun’s rays.
- Altering metabolism – Lowering their metabolic rate decreases internal heat generation.
- Feather compression – Compressing plumage reduces the layer of trapped, insulating air.
Behavioral Changes
Hot days often translate to changes in typical bird behaviors as well. Some alterations birds make in response to heat include:
- Seeking shade
- Panting or gular fluttering
- Wing drooping and stretching
- Dust bathing to absorb heat from bare skin
- Bathing frequently in water sources
- Reduced activity and lethargy
- Shifting feeding patterns to cooler parts of day
- Delaying nesting season and reproduction
- Abandoning nests and eggs if excessively hot
Tracking behaviors is one way scientists gauge the impact of temperatures on different species. Behavior changes signal when conditions surpass a bird’s comfort range and require extra effort to maintain homeostasis.
The Effects of Humidity
Humidity levels affect how well birds can use evaporative cooling to shed excess body heat. As moisture increases in the air, evaporation becomes less effective for dissipating heat.
Wet bulb temperature accounts for both ambient temperature and humidity. Scientists use wet bulb readings of approximately 80°F to indicate a critical high heat threshold for birds.
Some effects of high humidity on bird thermoregulation include:
- Greater panting as evaporative cooling becomes less efficient
- Seeking cooler microclimates away from sunlight
- Increased blood flow to skin to dissipate heat
- Possible disruption of embryonic development if nests are too hot and humid
Low humidity can also threaten birds by causing dangerous dehydration. Access to drinking water is imperative for birds in hot, arid environments. Species like sandgrouse and seedsnipe even soak their belly feathers to carry water back to the nest for their young.
Impact on Reproduction
Extreme heat can disrupt breeding and reproduction in a variety of ways:
- Lowered fertility from overheating testes in males
- Less energy for physically demanding courtship behaviors
- Altered timing of egg laying and breeding season
- Fewer eggs laid or decreased egg size
- More frequent egg abnormalities and defects
- Incubation difficulties regulating egg temperature
- Embryo mortality and decreased hatching success
- Chick developmental issues and higher mortality
All these factors combined can lower fecundity and breeding productivity. Some species may forgo nesting entirely during periods of extreme heat.
Nesting Vulnerabilities
Nesting parent birds and their eggs and chicks are especially vulnerable to hot weather threats including:
- Overheating embryos – Temperatures over 104°F can be lethal to developing chicks still in the egg.
- Overheating chicks – Nestlings have difficulty cooling themselves until feathered.
- Heat stressed parents – Foraging and feeding chicks becomes more taxing in heat.
- Dehydration – Eggs and chicks require constant moisture levels.
- Sun exposure – Nests in direct sun lack a cooling reprieve.
- Predators – Parents may be distracted from protecting nests against predators when trying to stay cool.
Nest failures skyrocket during heat waves as parents struggle to simultaneously cope with hot conditions themselves while also keeping eggs and chicks within normal temperature range.
Signs of Heat Stress
Behaviors indicating a bird is getting too hot include:
- Panting and gular fluttering
- Wing spreading and drooping
- Seeking shade
- Urinating on feet and legs
- Dust bathing
- Bathing frequently in water
- Decreased activity and lethargy
- Refusing to eat
- Visibly elevated respiratory rate
- Open mouth breathing
Physical symptoms of heat stress include:
- Elevated body temperature
- Dry, crusted, or scaly skin from dehydration
- Increased heart and respiratory rate
- Bright red or purple tinge to skin or eyes
- Swollen, purple tongue
- Panting or wheezing
- Vomiting
- Diarrhea
- Loss of coordination or balance
- Collapsing or convulsing
Without intervention, severe heat stress can lead to organ failure, brain damage, and death in birds. Providing accessible water, shade, and ventilation is crucial to cooling birds down in high temperatures. Emergency cooling with water misters, fans, air conditioning, and gel packs applied to the feet, wings, or head may be needed for birds displaying signs of heat exhaustion.
Providing Heat Relief
If temperatures near or above 90°F are forecast, here are some tips for protecting backyard birds and your feathered neighbors:
- Ensure access to clean, fresh drinking water – Change water frequently to prevent algae buildup and contamination.
- Mist baths – Misting on hot days keeps feathers damp for evaporative cooling. Drippers on branches or into bird baths help too.
- Provide shade – Trees, awnings, umbrellas, and shade cloth give sun relief in outdoor spaces birds frequent.
- Insulate and ventilate shelters – Proper housing insulation, ventilation, perches, and cool water helps captive outdoor birds stay healthy.
- Use fans, misters, air conditioning – Caged pet birds may rely on mechanical cooling when temperatures climb.
- Supplement diet – Extra protein, vitamins and minerals support birds during heat stress.
- Avoid handling – Trapping, banding, transporting, and other handling activities risk overheating birds.
Monitoring for signs of heat illness and taking steps to lower temperatures will help backyard and wild birds endure hot spells.
Indoor vs. Outdoor Temperatures
Birds kept exclusively indoors typically tolerate a more narrow, controlled temperature range compared to free-flying outdoor birds.
Pet birds will likely appear distressed when indoor temperatures exceed 85°F. Overheating can occur in temperatures above 90°F for confined indoor birds not acclimated to heat.
Outdoor birds experience wider temperature fluctuations both daily and seasonally. Tree and bush cover, nest insulation, hollows, burrows, and other microclimates all provide escape from the most intense sun and heat. Access to bathing water and shade means outdoor birds can utilize cooling behaviors not available to indoor pets.
However, extreme heat waves can still overwhelm acclimation abilities and threaten outdoor bird populations unaccustomed to such temperatures. All birds have limits to their heat tolerance ranges.
Species | Indoor Temperature Limit | Outdoor Upper Temperature Limit |
---|---|---|
Budgerigar | 90°F | 100-105°F |
Cockatiel | 85-90°F | 105-110°F |
Lovebird | 95°F | 110°F |
Conure | 85-90°F | 100-105°F |
Macaw | 85-90°F | 100-105°F |
Canary | 85-90°F | 100-105°F |
Finch | 90°F | 100°F |
Conclusion
90 degrees Fahrenheit and above is generally considered hot for most bird species. However, specific heat tolerance varies based on adaptations, size, native climate, access to water and shade, and other cooling behaviors.
While birds can acclimate to handle seasonal highs, extreme heat waves carry risks of hyperthermia, reproductive loss, and death if key resources are lacking. Providing clean drinking water, shade, mist baths, and ventilation can help backyard and wild birds ride out hot spells.
Being alert for signs of heat stress and ready to intervene with emergency cooling is important for safeguarding outdoor avians and pet birds when the mercury rises. With mindful preparation for summer scorchers, even sensitive species can weather temperatures approaching 100°F.